The ancient Gondorian capital of Osgiliath was built across the river Anduin, with half the city on one side of the river, and half on the other. The part that lay on the eastern bank was known as East Osgiliath (and presumably the other part of the city was West Osgiliath, though it is in fact never independently named).

For most of the city's existence, the two halves were joined by bridges across the Great River. One by one these were broken, until the Gondorians themselves destroyed the last of them in an attempt to hold back Sauron's forces, leaving a dangerous ford as the only way across from East Osgiliath. After this time the armies of the Red Eye controlled Osgiliath beyond the river, and there they built many rafts that they used to cross Anduin and lay siege to Minas Tirith.